1. Field of the Invention
The present invention pertains to a surface treatment apparatus, and particularly to an apparatus for planishing metal surfaces.
2. Description of Related Art
In machining, stamping presses are usually applied on sheet metal. During a stamping procedure, sheet metal may have sharp or uneven edges after stamping. Therefore, some bent edges are usually formed at these uneven edges of the sheet metal so that the sheet metal can become more aesthetic and safer to be further used.
Usually, such bent edges of the sheet metal are made by a punching machine using a method of punch crushing so that surfaces of the sheet metal can be punched to be smooth even though the edges are bent. However, this often results in the surface being abraded because of sliding friction between the punch and the sheet metal.
Therefore, a heretofore unaddressed need exists in the industry to overcome the aforementioned deficiencies and inadequacies.